Submitted to: Animal Nutrition Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 2, 1997
Publication Date: N/A
Technical Abstract: The purpose of this experiment was to study the effects of dietary protein in metabolic adaptations in birds given T3 at 28 d of age because knowledge is lacking about the role of dietary ingredients in this type of feeding regimen. Male broilers were fed diets containing either 120 or 300 g crude protein/kg from 7 to 28 d. At this time, one-half of each group was given that diet supplemented with 1 mg/ kg T3. Birds were sampled at 0, 2, 5, 7, 9 and 12 d following the switch. When T3 was added to either diet, IVL decreased by 50% after 5 d. Plasma IGF-I and T4 were greater while T3 and GH were less when birds were fed the higher level of crude protein. Plasma T3 increased and T4 decreased 3 d following the addition of T3 to diets containing either level of crude protein. Pancreatic amylase was greater and norepinephrine less in birds fed the higher level of crude protein, lending some support for neural control of pancreatic activities. Most metabolic changes in response to feeding T3 occurred within 2 to 5 d, suggesting that changes in intermediary metabolism preceded morphological changes. In addition, dietary protein levels do not appear to alter short-term responses to T3.